Dimensional Accuracy of Titanium Crown Fabricated by EBM and SLM

Objectives: Two processes are mainly applied for additive manufacturing with titanium: electron beam melting (EBM) and selective laser melting (SLM). EBM has a superior printing speed than SLM because of the greater-power laser. It allows us to fabricate prostheses with great efficiency, but there is no report to apply EBM to fabricating them. Thus, this study aimed to clarify the dimensional accuracy of the crown fabricated with EBM by comparing it with that fabricated by SLM.
Methods: A cylinder-shaped model as a simplified full crown was designed with the dimensions as follows: an outer diameter of 13 mm, an inner diameter of 10 mm, and a depth of 10 mm with a taper of 1/10. The model was fabricated with titanium by two methods: EBM (Arcam A2X) and SLM (Concept Laser M2). The designed data was arranged with the angle to the printing platform at 0, 45, and 90 degrees, respectively. Printing settings and post-processing were performed according to each manufacturer’s instructions. The dimensions of the crown, outer and inner diameters, and depth were measured. Then, changing rates from the designed value were calculated. The number of repetitions was set to five. ANOVA and Tukey’s test of multiple comparisons were performed.
Results: In the changing rates of outer diameter, SLM showed no significant difference between the printing angles (p>0.05), but EBM of 45 and 90 degrees was significantly larger than that of 0 degrees (p<0.05). In the inner diameter, 90 degrees of both methods showed significantly larger values than those of 0 degrees. In the depth, there were no significant differences between the angles in each method. In all measured points, SLM showed smaller values than EBM.
Conclusions: Arranging data with an angle of 90 degrees to the platform was the largest changing rate from the design. SLM showed better dimensional accuracy than EBM.